Tuesday 17 February 2015

calculus - Evaluating $sum_{k=1}^{infty}frac{1}{k(3k-1)}$

I am wondering if the sum
$$S=\sum_{k=1}^{\infty}\frac{1}{k(3k-1)}$$

has an exact expression. And when I plugged it into Wolfram Alpha it spitted out:
$$S=\frac{1}{6}\Big(-\sqrt{3} π + 9 \ln(3)\Big)$$
I am wondering how is the answer obtained? Is there a simple way of not using math beyond second year university to arrive to that answer?

No comments:

Post a Comment

real analysis - How to find $lim_{hrightarrow 0}frac{sin(ha)}{h}$

How to find $\lim_{h\rightarrow 0}\frac{\sin(ha)}{h}$ without lhopital rule? I know when I use lhopital I easy get $$ \lim_{h\rightarrow 0}...